From the 1940s to the mid-1950s, South African intellectual and political activist, Jacob Mfaniselwa Nhlapo, championed the forging of African political unity through harmonising writing systems for mutually related African language varieties. Owing to his diverse intellectual, professional and political background – a scholar, lawyer, journalist, and political activist – Nhlapo proposed harmonisation not as a purely linguistic enterprise, but as a project centred on the political economy of language. The motivation was to push back the frontiers of colonially imposed fragmentation of African identities through leveraging African language diversity for the political goals of uniting and empowering African people. The fragmentation of African people along ethnic and linguistic lines that prompted Nhlapo's ideas remains to this day, which means the political imperatives of harmonisation are still relevant now, probably more than ever before. In this article, I revisit the harmonisation proposal to explore those spheres of possibility and promise that it holds for mapping pan-African identities and literacies that transcend current inward-looking, nativist and nation-state-centric conceptions of being and becoming African. What promises do common writing systems for mutually related varieties of African languages hold for enhancing pan-African literacies, education and cross-cultural understanding both in and out of school contexts? To support the arguments advanced in this article, I draw on examples of Nguni languages and the Shona group of languages, with some passing remarks on the Sotho/Tswana group of languages.